It may be that it has a thicker shell or that it was a larger egg - larger eggs need lower humidity to lose enough moisture than smaller ones. Around here I need to incubate at 35% humidity to get them to lose enough weight, so it could be that even your dry humidity is too high.
I'd say try...
This is why it hasn't hatched. Your temp is low and if it's been this low all throughout incubation then you've been 2 and half degrees low the entire time. That's going to slow down your hatch a lot.
I can't really make out anything in your candling picture so I can't tell you if it died or...